Spin-dependent photoconductivity in nonmagnetic semiconductors at room temperature

By combining optical spin injection techniques with transport spectroscopy tools, we demonstrate a spin-photodetector allowing for the electrical measurement and active filtering of conduction band electron spin at room temperature in a simple nonmagnetic GaAsN semiconductor structure. By switching the polarization of the incident light from linear to circular, we observe a spin dependent photoconductivity change reaching up to 40% without the need of an external magnetic field. The spin dependent photoconductivity change relies on the efficient spin filtering effect of conduction band electrons on N-induced Ga self-interstitial deep paramagnetic centers.